A 16.6 kg object on a horizontal frictionless surface is attached to a spring with k = 2470 N/m. The object is displaced from equilibrium 28.1 cm horizontally and given an initial velocity of 12.6 m/s back toward the equilibrium position. What are (a) the motion's frequency, (b) the initial potential energy of the block-spring system, (c) the initial kinetic energy, and (d) the motion's amplitude?

Respuesta :

To solve this problem it is necessary to apply the concepts related to Period in a spring, elastic potential energy and energy in simple harmonic movement.

From the definition we know that the period can be expressed as

[tex]T = 2\pi \sqrt{\frac{m}{k}}[/tex]

Where

m= Mass

k = Spring constant

Our values are given as

m = 16.6Kg

K = 2470N/m

Therefore the period would be

[tex]T = 2\pi \sqrt{\frac{m}{k}}[/tex]

[tex]T = 2\pi \sqrt{\frac{16.6}{2470}}[/tex]

[tex] T = 0.515s [/tex]

PART A) The frequency is the inverse of the period therefore

[tex]f = \frac{1}{T}\\f = \frac{1}{0.515}\\f = 1.9417Hz[/tex]

PART B) Elastic potential energy depends on compression and elasticity therefore

[tex]PE = \frac{1}{2}kx^2[/tex]

[tex]PE = \frac{1}{2} (2470)(0.281)^2[/tex]

[tex]PE = 97.51J[/tex]

PART C) Kinetic energy depends on mass and speed therefore

[tex]KE = \frac{1}{2}mv^2\\KE = \frac{1}{2} (16.6)(12.6)^2\\KE = 1371.7J[/tex]

PART D) As energy is conserved, the total energy is equivalent to the dual ratio of the elasticity constant and the amplitude, mathematically,

[tex]KE+PE = \frac{1}{2}kA^2[/tex]

[tex]1371.7+97.51 = \frac{1}{2}2470A^2[/tex]

[tex]A = \sqrt{\frac{1415*2}{2470}}[/tex]

[tex]A = 1.07m[/tex]

Therefore the motion's amplitude is 1.07m

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